With the rapid development of science and technology, the formation of large-scale industrial integration has caused irreparable damages to the human living environment, and it has become very urgent for environmental protection. In recent years, electronic technology has been developing rapidly and the electronic products, especially the electronic waste products, increasingly affect the environment. At present, most of the electronic products are flame retardant by halogenated compounds which smell awful, and will generate a large amount of smoke, as well as release highly corrosive halogen hydride gases when they burn. It has been reported that carcinogenic substances such as dioxin and dibenzofuran are generated when the halogen-containing flame retardants are pyrolyzed under high temperature or burned. Europe has issued the Waste Electrical and Electronic Equipment Directive and the Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment, and it has been stipulated that the electronic products should not contain six substances such as lead, cadmium, mercury and hexavalent chromium, etc. since Jul. 1, 2006. Japan has also issued decrees about the halogen-free flame retardings, especially SONY has announced that all materials they use would be halogen-free materials. So, it is imperative to develop halogen-free and flame retardance substrate materials and this has become the technical focal point in the industry.
On the other hand, the safety of human life has attracted increasing concern from the society. In order to improve the safety and reliability of the electronic products, especially the safety and reliability of insulation materials (e.g. used for electrical machines, electrical appliances, etc.) applied in the conditions of humid environment, it has become an important developing direction to develop products with high insulation to ensure the safety and reliability of electronic products in recent years. The tested CTI (Comparative Tracking Index) of the copper-clad plate made of polymer materials refers to the highest voltage value measured after 50 drops of electrolyte (0.1% ammonium chloride aqueous solution) have been dropped on the surface of a material without forming any tracks To some extent, the CTI value is used to measure the insulating safety performance of the material, and the higher the value is, the better the insulation property the material has. Hence, the high-CTI products have become a trend of search and development in the electronics industry.
In recent years, high-CTI materials are mainly CEM-3 materials. However, since the lead-free standard has been performed in electronic and electrical industries and other related industries, the increasing requirements for the high-temperature environment where the products are applied are introduced accordingly, and new requirements are raised for the heat resistance of the materials. Therefore, the CEM-3 material cannot reach the above requirements. In addition, the problem of poor heat resistance is also existed in the existing high-CTI FR4 plates which are commonly cured with dicyandiamide, and the CTI of such plate is improved by adding aluminium hydroxide, thus resulting in poor heat resistance. So, it is urgent for the industry to develop a resin composition with both good heat resistance and high CTI, used in the circuit boards.